Android 无法将表迁移到Room do，因为在Sqlite中保存布尔值的方式有错误

我一直在尝试将我的应用程序迁移到Room。由于创建方式的原因，我正在处理一个无法直接迁移的特定表

字段是使用数据类型BOOL和BYTE而不是整数创建的

我已经尝试失败了：

将我的实体字段更改为Int/Boolean/Byte，并出现相同错误 创建类型转换器以将其另存为布尔值/字节 将类型affinity添加为affinity=1的我的实体的@ColumnInfo中未定义的 我的数据库SQL创建语句：

CREATE TABLE IF NOT EXISTS myTable (_id INTEGER PRIMARY KEY AUTOINCREMENT,
my_first_field BOOL NOT NULL DEFAULT 0,
my_second_field BYTE NOT NULL DEFAULT 0)

我的实体：

@Entity(tableName = "myTable")
data class MyTable(
        @PrimaryKey(autoGenerate = true)
        @ColumnInfo(name = "_id")
        var id: Int,

        @ColumnInfo(name = "my_first_field")
        var myFirstField: Boolean = false,

        @ColumnInfo(name = "my_second_field")
        var mySecondField: Byte = false
)

我经常遇到的错误是：

Expected:
TableInfo{name='my_table', columns={_id=Column{name='_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1}, my_first_field=Column{name='my_first_field', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}, my_second_field=Column{name='my_second_field', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=0}}, foreignKeys=[], indices=[]}
     Found:
TableInfo{name='my_table', columns={_id=Column{name='_id', type='INTEGER', affinity='3', notNull=true, primaryKeyPosition=1}, my_first_field=Column{name='my_first_field', type='BOOL', affinity='1', notNull=true, primaryKeyPosition=0}, my_second_field=Column{name='my_second_field', type='BYTE', affinity='1', notNull=true, primaryKeyPosition=0}}, foreignKeys=[], indices=[]}

有没有办法不创建迁移策略而直接进行迁移？

我相信您可以，在构建房间数据库之前：-

检查是否需要执行任何操作，例如使用：-

从sqlite_master中选择count，其中name='myTable'和instrsql'BOOL'和instrsql'BYTE'

然后检查结果

如果为0，则不执行其他操作，但为了安全起见，只有在oldmyTable为0时存在时才能使用DROP TABLE

仅当上述值返回1时，则：-

删除重命名后的原始表格，请参见下文和上文，以防其存在：-

如果存在oldmyTable，则删除该表； 使用定义另一个表

创建表如果不存在myOtherTable _idInteger主键自动递增， my_first_字段整数不为空默认值为0， 我的\u第二个\u字段整数不为空默认值0

i、 e.预期的模式

使用以下命令填充新表：

插入MyTherTable，从myTable中选择*； 使用以下命令重命名mytable：-

将表mytable重命名为oldmyTable； 使用原始名称重命名myOtherTable：-

将表myOtherTable重命名为mytable； 只有在测试时才明显删除重命名的原始表：-

如果存在oldmyTable，则删除该表

在确定迁移成功之前，您可能希望忽略此项。 最终的结果是该表应该如预期的那样

关于评论：-

问题是我需要迁移16-20个表

您可以使用以下内容：-

public static int preMigrateAdjustment(SQLiteDatabase mDB) {

    String original_rename_prefix = "old";
    String tempname_suffix = "temp";
    String newsql_column = "newsql";
    String[] columns = new String[]{
            "name",
            "replace(replace(sql,' BOOL ',' INTEGER '),' BYTE ',' INTEGER ') AS " + newsql_column
    };

    int count_done = 0;
    String whereclause = "name LIKE('" + 
            original_rename_prefix +
            "%') AND type = 'table'";
    Cursor csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
    while (csr.moveToNext()) {
        mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
    }


    whereclause = "type = 'table' AND (instr(sql,' BOOL ')  OR instr(sql,' BYTE '))";
    csr = mDB.query(
            "sqlite_master",
            columns,
            whereclause,
            null,null,null,null
    );
    while (csr.moveToNext()) {
        String base_table_name = csr.getString(csr.getColumnIndex("name"));
        String newsql = csr.getString(csr.getColumnIndex(newsql_column));
        String temp_table_name = base_table_name + tempname_suffix;
        String renamed_table_name = original_rename_prefix+base_table_name;
        mDB.execSQL(newsql.replace(base_table_name,temp_table_name));
        mDB.execSQL("INSERT INTO " + temp_table_name + " SELECT * FROM " + base_table_name);
        mDB.execSQL("ALTER TABLE " + base_table_name + " RENAME TO " + renamed_table_name);
        mDB.execSQL("ALTER TABLE " + temp_table_name + " RENAME TO " + base_table_name);
        count_done++;
    }
    whereclause = "name LIKE('" + 
            original_rename_prefix +
            "%') AND type = 'table'";
    csr = mDB.query("sqlite_master",null,whereclause,null,null,null,null);
    while (csr.moveToNext()) {
        mDB.execSQL("DROP TABLE IF EXISTS " + csr.getString(csr.getColumnIndex("name")));
    }
    csr.close();
    return count_done;
}

请注意，这并不是万无一失的，例如，如果您碰巧有以old开头的表，那么这些表将被删除。 上面假设第二次运行实际删除重命名的原始表。 附加的 在解决BOOL字节类型之后，在本例中使用5个具有相同模式的表进行实际测试，在该编码中发现了另一个问题

_id INTEGER PRIMARY KEY AUTOINCREMENT 

结果notNull=false，同时编码

@PrimaryKey(autoGenerate = true)
private long _id;

结果notNull=true

例如，假设未对AUTOINCREMENT NOT NULL进行编码的快速修复，预迁移调整中的行已从：-

mDB.execSQL((newsql.replace(base_table_name,temp_table_name)));

致：

mDB.execSQL((newsql.replace(base_table_name,temp_table_name)).replace("AUTOINCREMENT","AUTOINCREMENT NOT NULL"));

工作演示 创建和填充旧的售前桌。 在数据库帮助器OrginalDBHelper.java中创建和填充旧表：-

警告：这太简单了，不考虑它的缺陷就无法使用，并且仅用于演示。 房间的实体 为简洁起见，仅显示了5个表中的1个，即myTable0X.java

显然，这些必须仔细书写，以便与客房前的桌子相匹配

@Entity()
public class myTable0X {

    @PrimaryKey(autoGenerate = true)
    @ColumnInfo(name = "_id")
    private long id;

    @ColumnInfo(name = "my_first_field")
    private boolean my_first_field;
    @ColumnInfo(name = "my_second_field")
    private boolean my_second_field;

    public long getId() {
        return id;
    }

    public void setId(long id) {
        this.id = id;
    }

    public boolean isMy_first_field() {
        return my_first_field;
    }

    public void setMy_first_field(boolean my_first_field) {
        this.my_first_field = my_first_field;
    }

    public boolean isMy_second_field() {
        return my_second_field;
    }

    public void setMy_second_field(boolean my_second_field) {
        this.my_second_field = my_second_field;
    }
}

单个DAO接口DAOmyTablex.java 请注意，所有5个实体均已使用。 请注意，由于当前数据库版本为1，文件室要求增加版本号，因此版本号为2 将所有这些放在一起MainActivity.java 这包括3个核心阶段

建立售前室数据库。 把桌子换成适合的房间。 通过房间打开并移交数据库。 当应用程序启动时，它将自动执行第1和第2阶段。添加了一个按钮，单击该按钮后，将只执行第3阶段一次

最后，从表中提取数据，这实际上打开了房间数据库 其中一个表中的数据被输出到日志中

public class MainActivity extends AppCompatActivity {

    OriginalDBHelper mDBHlpr;
    Button mGo;
    mydb mMyDB;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mGo = this.findViewById(R.id.go);
        mGo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                goForIt();
            }
        });

        mDBHlpr = new OriginalDBHelper(this);
        Log.d("STAGE1","The original tables");
        dumpAllTables();
        Log.d("STAGE2", "Initiaing pre-mirgration run.");
        Log.d("STAGE2 A RESULT",
                String.valueOf(
                        PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
                        )
                ) + " tables converted."
        ); //<<<<<<<<<< CONVERT THE TABLES
        Log.d("STAGE2 B","Dumping adjusted tables");
        dumpAllTables();
        Log.d("STAGE2 C","Second run Cleanup");
        Log.d("STAGE2 DRESULT",
                String.valueOf(
                        PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
                        )
                ) + " tables converted."
        ); //<<<<<<<<<< CONVERT THE TABLES
        dumpAllTables();
        Log.d("STAGE3","Handing over to ROOM (when button is clicked)");
    }

    private void goForIt() {
        if (mMyDB != null) return;
        mMyDB = Room.databaseBuilder(this,mydb.class,OriginalDBHelper.DBNAME).addMigrations(MIGRATION_1_2).allowMainThreadQueries().build();
        List<myTable0X> mt0 = mMyDB.dbDAO().getAllFrommyTable0();
        List<myTable1X> mt1 = mMyDB.dbDAO().getAllFrommyTable1();
        List<myTable2X> mt2 = mMyDB.dbDAO().getAllFrommyTable2();
        List<myTable3X> mt3 = mMyDB.dbDAO().getAllFrommyTable3();
        List<myTable4X> mt4 = mMyDB.dbDAO().getAllFrommyTable4();
        for (myTable0X mt: mt0) {
            Log.d("THIS_MT","ID is " + String.valueOf(mt.getId()) + " FIELD1 is " + String.valueOf(mt.isMy_first_field()) + " FIELD2 is " + String.valueOf(mt.isMy_second_field()));
        }
        // etc.......
    }

    private void dumpAllTables() {
        SQLiteDatabase db = mDBHlpr.getWritableDatabase();
        Cursor c1 = db.query("sqlite_master",null,"type = 'table'",null,null,null,null);
        while (c1.moveToNext()) {
            Log.d("TABLEINFO","Dmuping Data for Table " + c1.getString(c1.getColumnIndex("name")));
            Cursor c2 = db.query(c1.getString(c1.getColumnIndex("name")),null,null,null,null,null,null);
            DatabaseUtils.dumpCursor(c2);
            c2.close();
        }
        c1.close();
    }

    public final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            /**NOTES
            //Tried the pre-migration here BUT SQLiteDatabaseLockedException: database is locked (code 5 SQLITE_BUSY)
            //Cannot use SupportSQLiteDatabase as that locks out access to sqlite_master
            //PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Initial run
            //PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Cleanup run
            */
        }
    };
}

最后一行是：-

2019-05-19 13:20:03.090 D/THIS_MT: ID is 1 FIELD1 is false FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 2 FIELD1 is true FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 3 FIELD1 is true FIELD2 is true
2019-05-19 13:20:03.090 D/THIS_MT: ID is 4 FIELD1 is false FIELD2 is true

---

添加更多代码plz@MMOHADADZAABIRI你认为什么有用/必要的其他代码？SQLite没有“布尔”或“字节”类型…使用整数。我知道SQLITE没有布尔值或字节。实际上，如果数据库是新的，则不会发生此错误，因为数据库字段被初始化为整数，而不是字节或BOOL。我的问题是如何避免破坏我的表并将信息复制到一个新表中。这是我管理它的实际方法，因为似乎除了迁移它之外没有其他方法。问题是数据库已经创建并填充。问题是我需要迁移16-20个表。很多如果没有更好的答案，或者没有直接的方法，我会投票并选择它作为正确答案。@AndresOller您可以使用类似select name、REPLACESQL、“BOOL”、“INTEGER”、“BYTE”、“INTEGER”的内容作为sqlite_master的新闻SQL，其中instrsql、“BOOL”或instrsql“BYTE”；要驱动多表进程 党卫军。因此，对于每一行，如果没有，则不执行任何操作，因为您拥有表名和调整后的SQL。

@Dao
public interface DAOmyTablex {

    @Query("SELECT * FROM myTable0X")
    List<myTable0X> getAllFrommyTable0();

    @Query("SELECT * FROM myTable1X")
    List<myTable1X> getAllFrommyTable1();

    @Query("SELECT * FROM myTable2X")
    List<myTable2X> getAllFrommyTable2();

    @Query("SELECT * FROM myTable3X")
    List<myTable3X> getAllFrommyTable3();

    @Query("SELECT * FROM myTable4X")
    List<myTable4X> getAllFrommyTable4();

    @Insert
    long[] insertAll(myTable0X... myTable0XES);

    @Insert
    long[] insertAll(myTable1X... myTable1XES);

    @Insert
    long[] insertAll(myTable2X... myTable2XES);

    @Insert
    long[] insertAll(myTable3X... myTable3XES);

    @Insert
    long[] insertAll(myTable4X... myTable4XES);

    @Delete
    int delete(myTable0X mytable0X);

    @Delete
    int delete(myTable1X mytable1X);

    @Delete
    int delete(myTable2X mytable2X);

    @Delete
    int delete(myTable3X mytable3X);

    @Delete
    int delete(myTable4X mytable4X);

}

@Database(entities = {myTable0X.class, myTable1X.class, myTable2X.class, myTable3X.class, myTable4X.class},version = 2)
public abstract class mydb extends RoomDatabase {
    public abstract DAOmyTablex dbDAO();
}

public class MainActivity extends AppCompatActivity {

    OriginalDBHelper mDBHlpr;
    Button mGo;
    mydb mMyDB;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        mGo = this.findViewById(R.id.go);
        mGo.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                goForIt();
            }
        });

        mDBHlpr = new OriginalDBHelper(this);
        Log.d("STAGE1","The original tables");
        dumpAllTables();
        Log.d("STAGE2", "Initiaing pre-mirgration run.");
        Log.d("STAGE2 A RESULT",
                String.valueOf(
                        PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
                        )
                ) + " tables converted."
        ); //<<<<<<<<<< CONVERT THE TABLES
        Log.d("STAGE2 B","Dumping adjusted tables");
        dumpAllTables();
        Log.d("STAGE2 C","Second run Cleanup");
        Log.d("STAGE2 DRESULT",
                String.valueOf(
                        PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()
                        )
                ) + " tables converted."
        ); //<<<<<<<<<< CONVERT THE TABLES
        dumpAllTables();
        Log.d("STAGE3","Handing over to ROOM (when button is clicked)");
    }

    private void goForIt() {
        if (mMyDB != null) return;
        mMyDB = Room.databaseBuilder(this,mydb.class,OriginalDBHelper.DBNAME).addMigrations(MIGRATION_1_2).allowMainThreadQueries().build();
        List<myTable0X> mt0 = mMyDB.dbDAO().getAllFrommyTable0();
        List<myTable1X> mt1 = mMyDB.dbDAO().getAllFrommyTable1();
        List<myTable2X> mt2 = mMyDB.dbDAO().getAllFrommyTable2();
        List<myTable3X> mt3 = mMyDB.dbDAO().getAllFrommyTable3();
        List<myTable4X> mt4 = mMyDB.dbDAO().getAllFrommyTable4();
        for (myTable0X mt: mt0) {
            Log.d("THIS_MT","ID is " + String.valueOf(mt.getId()) + " FIELD1 is " + String.valueOf(mt.isMy_first_field()) + " FIELD2 is " + String.valueOf(mt.isMy_second_field()));
        }
        // etc.......
    }

    private void dumpAllTables() {
        SQLiteDatabase db = mDBHlpr.getWritableDatabase();
        Cursor c1 = db.query("sqlite_master",null,"type = 'table'",null,null,null,null);
        while (c1.moveToNext()) {
            Log.d("TABLEINFO","Dmuping Data for Table " + c1.getString(c1.getColumnIndex("name")));
            Cursor c2 = db.query(c1.getString(c1.getColumnIndex("name")),null,null,null,null,null,null);
            DatabaseUtils.dumpCursor(c2);
            c2.close();
        }
        c1.close();
    }

    public final Migration MIGRATION_1_2 = new Migration(1, 2) {
        @Override
        public void migrate(SupportSQLiteDatabase database) {
            /**NOTES
            //Tried the pre-migration here BUT SQLiteDatabaseLockedException: database is locked (code 5 SQLITE_BUSY)
            //Cannot use SupportSQLiteDatabase as that locks out access to sqlite_master
            //PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Initial run
            //PreMigrationAdjustment.preMigrateAdjustment(mDBHlpr.getWritableDatabase()); //Cleanup run
            */
        }
    };
}

2019-05-19 13:18:12.227 D/STAGE1: The original tables
2019-05-19 13:18:12.244 D/STAGE2: Initiaing pre-mirgration run.
2019-05-19 13:18:12.281 D/STAGE2 A RESULT: 5 tables converted.
2019-05-19 13:18:12.281 D/STAGE2 B: Dumping adjusted tables
2019-05-19 13:18:12.303 D/STAGE2 C: Second run Cleanup
2019-05-19 13:18:12.304 D/STAGE2 DRESULT: 0 tables converted.
2019-05-19 13:18:12.331 D/STAGE3: Handing over to ROOM (when button is clicked)

2019-05-19 13:20:03.090 D/THIS_MT: ID is 1 FIELD1 is false FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 2 FIELD1 is true FIELD2 is false
2019-05-19 13:20:03.090 D/THIS_MT: ID is 3 FIELD1 is true FIELD2 is true
2019-05-19 13:20:03.090 D/THIS_MT: ID is 4 FIELD1 is false FIELD2 is true